A vehicle air conditioning system is a system which maintains the temperature inside a vehicle at a lower temperature than the external temperature using refrigerant. The vehicle air conditioning system includes a compressor, a condenser, and an evaporator in order to form a refrigerant circulation cycle. The compressor is a device which compresses and transfers refrigerant, and is operated by the power of an engine or the driving of a motor.
In a double-headed swash type compressor which is a type of reciprocating compressor, a disk-shaped swash plate is installed to a shaft to which the power of an engine is transferred. A plurality of pistons is installed around the swash plate with a shoe interposed therebetween. When the swash plate rotates, the pistons reciprocate in respective cylinder bores formed in a cylinder block, thereby allowing refrigerant to be introduced, compressed, and discharged. In this case, a valve plate to control the introduction and discharge of the refrigerant is installed between a housing and the cylinder block.
In a conventional double-headed swash type compressor, a sliding bearing is installed between a shaft and a shaft bore in order to reduce wear and friction due to the rotation of the shaft. However, the sliding bearing is made of a metal material coated with fluorine resin, and therefore, when a hole for movement of refrigerant is processed in the sliding bearing, the accuracy of the hole may be deteriorated and burrs may be generated due to the high elongation of the sliding bearing.
In addition, in the initial stage where the double-headed swash type compressor is driven, the antiwear between the shaft and the sliding bearing is not stably performed, which may lead to an increase in friction due to the wear therebetween and thus leakage of refrigerant when the compressor is used for a long time.